Refrigeration system having tandem compressor arrangement



March 31, 1970 s. A. PARKER REFRIGERATION SYSTEM HAVING TANDEM COMPRESSOR ARRANGEMENT Filed July 29, 1968 /1\/ VEN 7 0R. S/DNE YA. PARKER ATTORNEYS United States Patent O 3,503,223 REFRIGERATION SYSTEM HAVING TANDEM COMPRESSOR ARRANGEMENT Sidney A. Parker, Fort Worth, Tex., assignor to Lennox Industries Inc., a corporation of Iowa Filed July 29, 1968, Ser. No. 748,263 Int. 'Cl. F25b 31/02 US. Cl. 62510 4 Claims ABSTRACT OF THE DISCLOSURE A refrigeration system including a pair of compressors connected in tandem is provided with check-valve means for preventing contamination of one compressor in the event of damage or malfunction of the second compressor.

BACKGROUND OF THE INVENTION This invention relates to a refrigeration system including a pair of compressors arranged in tandem, and, more particularly to a refrigeration system including such arrangement which incorporates check-valve means for preventing contamination of one compressor in the event of damage or malfunction of the second compressor.

Refrigeration systems incorporating two or more compressors in tandem have been utilized to provide for a form of capacity control. Assuming, for example, that the two compressors of equal capacity are employed, if one compressor is operative, then the system will be operating at 50 percent of capacity and if both compressors are operating, then 100 percent capacity can be obtained.

Normally in such refrigeration system, the discharge lines from each of the compressors are connected to a common discharge gas header or conduit means, which, in turn, communicates with the condenser.

The condenser is connected in the refrigeration system with expansion means and an evaporator. The outlet from the evaporator is connected to a suction gas header or conduit means for returning the suction gas in separate lines to the compressors. In use, if one compressor fails, for example, if a valve should break or if the compressor electric drive motor burns out, particles may break loose into the space between the compression mechanism and the outer casing. Such particles may then pass from the compressor that has failed to the operating compressor and caused damage to the operating compressor.

An object of the present invention is to provide a refrigeration system including a pair of compressors connected in tandem with check-valve means for preventing discharge of gas and particles from within the damage compressor to the other compressor. Other objects and advantages of the present invention will be made more apparent hereinafter.

BRIEF DESCRIPTION OF THE DRAWING Preferred embodiments of the present invention are shown in the accompanying drawing, wherein like numerals refer to like elements in the various views and wherein:

FIG. 1 is a schematic view of a refrigeration system incorporating hermetic refrigerant compressors arranged in tandem, such system embodying the principles of the present invention;

FIG. 2 illustrates a modified tandem compressor arrangement embodying principles of the present invention;

FIG. 3 illustrates a modified form of check-valve that might be utilized in the arrangement of FIG. 2; and

FIG. 4 is a cross-section of the modified check-valve arrangement taken generally along line 44 of FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to FIG. 1, there is illustrated a refrigeration system 10 having a pair of compressors 12 and 14 connected therein in tandem to one another. The. compressors 12 and 14 will be described generally as they are of known design and the details thereof form no part of the present invention. The respective compression mechanisms 16 and 18 within the compressors 12 and 14 compress the refrigerant gas and discharge same through the discharge gas conduits 20 and 22, respectively to a condenser 24. Conduits 20 and 22 may be joined to a discharge gas header that is in turn connected to the condenser 24. The condensed refrigerant passes from the condenser 24 through an expansion means 26 which may be, for example, a capillary tube or a thermal expansion valve to the evaporator 28. From the evaporator 28, the refrigerant gas passes to a suction gas conduit means indicated generally by the numeral 30 from which the refrigerant passes back to the compressors 12 and 14, respectively, into the space between the compression mechanism and the outer housing which is normally at suction pressure when the compressors are operating. The suction gas conduit means or header means 30 includes a T-member 32 having connections at opposite ends to fittings 34 and 36 which are in turn connected to compressors 12 and 14.

Cooperating with the end of each of the fittings 34 and 36 is a check-valve means 38, 40, respectively. The checkvalve means 38 and 40 include spring means 39 and 41 for biasing the valves 42 and 43, respectively, to the closed position. Thus, the check-valves 38 and 40 function to permit passage of suction gas into the compressors 12 and 14, but discharge of suction gas from the compressors to the suction gas header or conduit means is prevented.

In normal operation, the suction gas returning to the compressors 12 and 14 from the evaporator 28 will overcome the bias of the springs 39 and 41, causing the valves 42 and 43 to open. In the event of malfunction of one of the compressors, for example, the compressor 14, the forces urging the valve 43 to the closed position Will overcome the suction gas pressure urging the valve open and the valve 43 will be closed. Assuming the malfunction were caused by motor failure, any particles of insulation or the like within the damaged compressor 14 would be confined within the compressor and upon closure of the valve 43, such contaminants could not pass through the suction gas conduit means 30 to the operative compressor 12. The check-valve means 38 will function in a similar manner to prevent contamination of the operative compressor 14 in the event of malfunction and failur of the compressor 12.

Referring now to FIG. 2, there is ilustrated a tandem refrigerant compressor arrangement incorporating semihermetic type compressors 12' and 14' having the suction gas inlets to the compressors formed by a unitary suction gas header means 30' comprising a generally annular housing secured to each of the compressor housings and having an inlet 31 that is adapted to be connected to the suction line communicating with the evaporator of the refrigeration system. Provided within the suction gas header 30' are a pair of wall members 46 and 48, each of which has an opening 49 and 50, respectively, therein. The suction gas openings 49 and 50 are closed by checkvalve means 38 and 40' which function in the same manner as the check-valve means 38 and 40.

It will be understood that the discharge gases from the compressors 12 and 14' pass through separate discharge lines to a. common header and then to the condenser of a refrigeration system as in the embodiment of FIG. 1. The refrigerant gas returns to the suction gas header 30' and then to the compressors 12' and 14 through openings 49 and 50 "in' wall members 46 and 48. The two check-valve means 38 and 40' function as the checkvalves 38 and 40, respectively, to prevent cross-contamination of the compressors 12 and 14' in the event of failure of one of them.

Referring now to FIGS. 3 and 4, there is illustrated a modified form of check-valve means that may be employed in place of the check-valve means 38', 40" of FIG. 2. The check-valve 142 is comprised of a flapper-type valve which is secured at its upper end to the wall 46 by means'of rivets or like fastening members 54. The valve 142 is made from a relatively thin, flexible material, such as a spring steel. In this manner, the spring normally used to bias the valve closed is omitted and the valve is biased closed by the inherent resiliency of the metal.

There has been provided by the present invention a refrigeration system including at least a pair of compressors connected in tandem, such compressors being I interconnected in a refrigeration system with condenser means, expansion means and evaporator means, and the system being provided with means for preventing contamination of one compressor in the event of damage or malfunction of the second compressor. The contamination preventing means comprises check-valve means associated with the suction gas inlet to each compressor for preventing the discharge of gas and contaminants from Within the damaged compressor to the operating compressor. The check-valve means are preferably one-way check-valves, which are adapted to be biased to the closedposition. Spring means may be used to provide the biasing force for closing the valve means or alternately the valve means may be comprised of flapper valves biased closed by the normal resiliency of the metal and the pressure within the compressor.

I claim:

1. In a refrigeration system including a pair of compressors having motor means therein, condenser means,

thermal expansion means and evaporator means, the compressors being connected in parallel with the condenser means, expansion means and evaporator means by discharge line means and by suction line means, the improvement comprising means for preventing contamination of one compressor in the event of damage or malfunction of the second compressor, such preventing means comprising check valve means for each compressor for permitting flow of refrigerant from the suction line means to the respective compressors but preventing discharge of gas and contaminants from withinthe da maged compressor to the suction line means for passage to the other compressor.

2. A refrigeration system as in claim 1, wherein the check-valves are biased closed by spring means and are normally opened by gas pressure from the suction line means when the compressors are operative.

3-. A refrigeration system as in claim 1, wherein the refrigerant compressors are connected by a common suction gas header and separate checkvalve means are provided in the suction gas header.

4. A refrigeration system as in claim 1 wherein the check valve means comprise a one-way valve member disposed in each compressor.

References Cited UNITED STATES PATENTS 

